Battery monitoring unit

Abstract

The invention relates to a battery monitoring unit (10) comprising an interface (12) configured to receive a voltage (14A, 14B) of each battery block (22) of a battery (1), the battery block comprising at least two battery cells (24) connected in parallel to each other, the battery being coupled to the battery monitoring unit (10) and comprising at least two battery blocks (22), wherein an evaluation unit (16) is provided, which is configured to compare the voltages (14A, 14B) of at least two battery blocks (22) connected in series received from the interface (12) and to output a signal (18) depending on the comparison result.

Description

Technical Field

[0001] This invention relates to a battery monitoring unit, particularly for monitoring the connection status of parallel and / or series battery packs, which are composed of battery cells connected in parallel. The invention also relates to corresponding batteries or traction batteries for electric vehicles composed of battery packs. Background Technology

[0002] In electrochemical energy storage devices used as traction batteries, particularly in lithium-ion batteries, multiple battery cells are typically connected in series and / or parallel to form a battery pack. This allows the battery pack to achieve the total capacity and total voltage required for the corresponding end use, such as specific traction batteries for electric and hybrid vehicles.

[0003] Voltage taps may exist between battery packs composed of parallel battery cells to determine the voltage applied to these battery packs accordingly. For example, the determined voltage can be transmitted to a battery management system, which can detect overvoltages occurring during battery cell charging or undervoltages occurring during battery cell discharging, and accordingly avoid them through appropriate measures (such as terminating the charging process).

[0004] Typically, these batteries, especially those used in hybrid and electric vehicles, are interconnected in a way that provides a total voltage of several hundred volts, while the voltage applied to each individual cell is usually only a few volts due to the series connection. However, if these batteries fail—for example, if the electrical connections of some or all of the cells in the battery pack fail—a fraction of the battery voltage, or in extreme cases, even the full battery voltage (which can reach 800 volts or higher in many cases), will be applied to that point in the circuit. In this situation, a short circuit and arcing can occur, causing serious damage to the battery or the entire vehicle.

[0005] The battery cells in the battery pack may fail one after another, which may be related to the gradual change in the voltage of the corresponding battery pack.

[0006] While known systems can shut down a battery when its voltage exceeds a nominal or previously stored value, the reliability of this approach is limited. This is because these values ​​may be determined for a specific battery configuration or series and do not perfectly match the individual cells that need to be monitored in a particular situation. Furthermore, a battery's state can change significantly over its lifespan, influenced by factors such as its lifespan, charge and discharge times, specific application loads, runtime, operating conditions, and / or environmental conditions. Therefore, these general nominal values ​​may not apply to individual cells and / or their state, and thus these values ​​should include a wide tolerance range. Consequently, in some cases, the battery's critical state may not be determined until later in the process.

[0007] Therefore, it is necessary to monitor batteries more accurately in order to detect faults early, and preferably to be able to be used for multiple batteries and / or multiple types of batteries. Summary of the Invention

[0008] Based on known prior art, the purpose of this invention is to provide an improved battery monitoring unit.

[0009] The object of the present invention is achieved by a battery monitoring unit having the features described in this application. Advantageous embodiments can be derived from the specification and drawings.

[0010] Therefore, the present invention proposes a battery monitoring unit, the device including an interface configured to receive voltage via a corresponding voltage tap of each battery pack, each battery pack including at least two battery cells connected in parallel with each other, the battery being coupled to the battery monitoring unit and including at least two battery packs. According to the invention, an evaluation unit is provided, configured to compare the voltages received from at least two series-connected battery packs in the battery, and output a signal based on the comparison result.

[0011] A battery pack can be either a battery module that integrates mechanical and electrical components, or a logical unit within a battery module or battery. A key characteristic of a battery pack is that it consists of at least two battery cells connected in parallel and has its own voltage tap, regardless of the battery's mechanical structure and spatial layout.

[0012] Each battery pack typically has the same number of battery cells, which are connected in parallel. If the voltage of each cell conforms to the specified operating conditions, the voltage comparison results of at least two battery packs will be substantially similar, except for common measurement fluctuations. However, if one or more cells in a battery pack do not operate as specified, the voltage of that battery pack will differ from the voltages of the other cells in the battery pack pair. In other words, even minute voltage variations deviating from normal or expected conditions can be detected by comparing the tap voltages of at least two series-connected battery packs.

[0013] The voltage comparison between the voltage taps of each battery pack can be easily achieved by subtracting the measured value. If the batteries are operating as expected under normal conditions, the difference will be essentially zero; if a voltage difference exists, the difference will deviate from zero.

[0014] The comparison of tap voltages between the voltage taps of the battery pack can also be achieved by generating a quotient from the measured values. When the battery is operating normally, the quotient is approximately 1; if there is a deviation in the measured voltage, the quotient will deviate from 1.

[0015] The comparison of measured voltages can also be performed using other calculation comparison methods.

[0016] In this way, even slight differences in voltage can indicate the wear and tear or impending wear of a battery cell, enabling highly accurate monitoring of the battery's condition. This is particularly advantageous when battery packs are highly parallelized and each pack contains a relatively large number of cells connected in parallel, especially because it allows for early detection of existing faults that could otherwise lead to serious or even dangerous malfunctions.

[0017] As a safety measure, a membrane-based current interruption device (CID) can be installed in the battery cell. This device selectively interrupts the electrical contacts when excessive gas is generated in the cell, such as due to aging, manufacturing failure, or overload, or when the associated pressure in the cell increases. Early detection of this interruption can prevent a chain reaction caused by a corresponding increase in current in the remaining cells of the battery pack. Therefore, safety is greatly improved. The cessation of operation of one or more battery cells in the battery pack can be detected by the proposed battery monitoring unit.

[0018] Furthermore, regardless of the specific battery configuration, the battery monitoring unit can generally monitor the battery. This is because by comparing at least two series-connected battery packs, the process of comparing absolute, individual voltage values ​​with the voltages specified for the corresponding battery pack type and / or configuration can be eliminated.

[0019] Similarly, once the difference—for example, the difference used for comparison—is determined, the signal output can generally be performed without considering the power supply or the corresponding battery pack. Any changes in battery state that may occur during the battery's lifespan, such as those caused by battery life, charging and discharging times, specific application loads, operating time, operating conditions, and / or environmental conditions, can also be automatically taken into account, as these changes are not significantly different for the individual battery packs during operation. Therefore, battery state can be precisely monitored, allowing for early detection of faults throughout the battery's lifespan.

[0020] The battery monitoring unit can be a standalone module or an integrated component within the battery control unit. The battery monitoring unit includes an evaluation unit for evaluating received voltage or measurement values ​​and determining or calculating corresponding comparison values ​​for at least two series-connected battery packs. The interface may exist as a hardware component, for example, implementing electrical coupling to a corresponding voltage tap, and / or at least partially including computer-readable logic units for transmitting corresponding measurement signals or data.

[0021] Furthermore, various series-connected battery packs can be compared, for example, to determine differences. For instance, differences can be determined for battery packs that are not directly adjacent to each other and / or for battery packs that are, conversely, multiple battery packs interconnected to form a single battery pack. Different differences can be determined substantially simultaneously or sequentially, allowing multiple differences to be considered in the output signal, or a signal to be output for each individual difference.

[0022] For example, in the case of multiple battery packs, the voltages of non-adjacent battery packs can be compared with each other, and the comparison can be repeated for corresponding sequential or adjacent battery packs. Based on these voltage values, a potential fault can be inferred or determined within a single battery pack. However, multiple battery packs arranged side-by-side, such as two adjacent battery packs, can also be compared with a corresponding number of side-by-side non-matching battery packs. This allows conclusions to be drawn, for example, whether a potential fault exists in a specific area of ​​the battery pack.

[0023] Similarly, a degree of safety redundancy can be provided, where the comparison values, such as differences, between each battery pack and one or more other battery packs or all other battery packs are determined individually. By comparing all battery packs with each other, conditions such as voltage fluctuations can be masked, further improving the accuracy of monitoring.

[0024] The evaluation unit of the battery monitoring unit is preferably capable of comparison, for example, determining at least the difference between corresponding adjacent battery packs. The term "adjacent" should be understood as a continuous arrangement in series in the direction of the power supply terminals or corresponding voltage taps, such that, for example, the voltage of one battery pack is compared with the voltage of another battery pack that is closer to the power supply terminals than the battery pack itself.

[0025] This allows for the identification of potential faults in individual battery packs, and the connection between tap voltages and the corresponding battery packs can be established without configuring data. In other words, signals can be output for specific individual battery packs, enabling highly precise monitoring of battery status.

[0026] Furthermore, the evaluation unit of the battery monitoring unit is preferably configured to output a signal when the corresponding difference exceeds a predetermined threshold. For example, the threshold could be a characteristic representing a voltage rise corresponding to the voltage of one or more battery cells, where the battery cells may, for example, provide standardized power. Similarly, the threshold could also be selected for a predetermined increase in ohmic resistance, which is a characteristic representing the presence of a potential fault, such as a fault in one or more battery cells. In this regard, the voltage drop across the battery pack at a specific current can be measured, and the ohmic resistance of the battery pack can be inferred or derived from this.

[0027] Alternatively or additionally, the evaluation unit of the battery monitoring unit may also be configured to output a signal when the ratio of the difference to the voltage value of at least one battery pack that forms the difference reaches 0.01:1.0 to 0.25:1.0, preferably 0.05:1.0 to 0.20:1.0.

[0028] In other words, the difference can be determined as a percentage of the tap voltage of a particular battery pack, preferably a percentage of the corresponding lower voltage. If this percentage is between 1% and 25% of the voltage, or between 5% and 20%, or exceeds this value, a signal can be output. For example, if the difference exceeds approximately 15%, a signal can be output. The percentage can be predetermined such that typical voltage fluctuations are ignored for signal output, indicating a fault with sufficient probability, or even that a specific fault is predetermined as a percentage. Therefore, the percentage can be selected such that an inspection or action is required when this percentage is exceeded.

[0029] Another advantage of this embodiment is that, generally speaking, the battery can be monitored regardless of its configuration. Therefore, absolute power values ​​or thresholds are not required, allowing for battery state monitoring for each type of battery, independent of its specific configuration. Thus, a percentage can serve as a threshold without corresponding to an absolute voltage value. This is also advantageous for addressing potential changes in battery performance over its lifespan, particularly since it can be assumed that the performance of each battery bank changes in a similar manner over time, for example, with variations in charge cycles and operating conditions. Regardless of the lifespan, a prescribed ratio or percentage is meaningful for fault detection.

[0030] To make the signal output more specific or to take into account various operating states, the difference between the idle state and the load state can be determined under a known current, and the corresponding differences can be compared. In this way, the influence of different charging states of the battery cells can be eliminated through calculation and taken into account when outputting the signal.

[0031] This type of inspection may occur intermittently or over a long period during the battery's routine or normal operation. Furthermore, any manufacturing defects can also be detected using this method; for example, it can be directly inspected or tested as an end-of-production check after manufacturing is completed in the production workshop.

[0032] For example, this method can be used to identify defective solder joints in the entire battery pack or sub-region when the corresponding connecting strips or busbars are not properly arranged due to manufacturing defects or tolerances, resulting in all or most of the solder joints of the battery pack or corresponding parallel battery cells being improperly completed. These solder joints may fail during battery use due to excessive transition resistance. Therefore, the benefit of checking for differences at low current is that this undesirable, potentially dangerous condition can be detected and prevented from occurring.

[0033] Similarly, the process requirements for battery cell electrical contacts can be minimized, especially since faults can be reliably detected afterward. This simplifies or accelerates production, potentially enabling faster and more cost-effective manufacturing.

[0034] Furthermore, the behavior of the corresponding battery pack, or its development over its lifespan, can be variable, fluctuating, or changing depending on the operating conditions. Additionally, a potential failure of a single battery cell may not necessarily trigger a current-interrupting device. However, the quality of an individual battery cell may degrade over the battery's lifespan, which will be reflected in the corresponding voltage.

[0035] Therefore, the evaluation unit of the battery monitoring unit can be configured to record the progress or process of corresponding comparison values, such as differences, and output a signal when the progress deviates from a predetermined progress. In this way, negative trends can be detected at an early stage, and the corresponding battery pack can be identified so that defective battery cells, battery packs containing defective battery cells, battery modules of battery packs containing defective battery cells, or the entire battery can be replaced accordingly. The predetermined progress can be stored in the battery monitoring unit and used as part of the comparison along with the recorded progress, for example, as part of determining the difference or output signal.

[0036] For example, the predetermined progress can include the expected progress of the difference over a specific lifespan, or it can specify a more complex polynomial progress, which is compared with the recorded progress through statistical evaluation and correlation, and a signal is output if the correlation deviates from the specified tolerance range.

[0037] The evaluation unit of the battery monitoring unit is preferably configured to determine the total resistance of a given battery pack (or multiple battery packs) based on a corresponding comparison and, for example, a difference. The total resistance is a characteristic of the battery pack's operating state. In this way, the ohmic resistance under operating conditions can be input to the difference evaluation and signal output, where the resistance value may be high, for example, under maximum operation or full load conditions due to relatively high temperatures. However, if the total resistance, for example, the total resistance under normal operation, differs from the specified or expected total resistance, and that resistance is correspondingly higher, then the higher total resistance may be a characteristic of a battery fault, and a signal can be output accordingly.

[0038] Furthermore, the evaluation unit of the battery monitoring unit may include a current / voltage characteristic curve and be configured to output a signal based on the corresponding difference and the current / voltage characteristic curve. Based on the current / voltage characteristic curve (e.g., based on empirical values), the corresponding change in the resistance of the corresponding battery pack at a specific difference can be calculated, which may be a characteristic of a specific fault. In other words, more accurate fault detection can be performed based on the characteristic curve.

[0039] The characteristic curves can also be provided by a central unit, such as a server or a central vehicle control system. Therefore, the evaluation unit of the battery monitoring unit is preferably configured to receive battery-related characteristic data via an interface, transmit or communicate the data to the central unit, and receive at least one current / voltage characteristic curve from the central unit in response to the transmitted characteristic data. The battery monitoring unit is configured to output signals based on the corresponding differences and current / voltage characteristic curves. To send and receive the corresponding data, the battery monitoring unit may include a communication module, or may be communicatively coupled to a communication module of the battery control unit. One advantage of identifying at least one characteristic curve is that the latest characteristic curve can be obtained, and specific characteristic data can be taken into account, thereby specifying the characteristic curve for the corresponding battery.

[0040] Characteristic data may include battery type, the number of parallel cells in each battery pack, cell type, number of series-connected battery packs, battery application, and / or battery-related operational data. Therefore, characteristic curves can be further specified, which can be adjusted based on the battery, battery structure, battery application, and / or battery development over its lifespan. This allows for highly accurate determination of changes in total resistance, etc., by comparing differences and characteristic curves, thereby further improving the early detection of potential faults. Any thresholds can also be adjusted accordingly, and tolerance ranges can be narrowed.

[0041] Furthermore, characteristic curves relevant only to the battery can be identified based on feature data. The characteristic curves provided by the central unit can be based on empirical values ​​of actual tap voltages and / or on comparative data and / or on differences actually determined for batteries with comparable characteristic data. Therefore, the battery monitoring unit is preferably configured to transmit the received voltage and / or corresponding comparative data and / or corresponding differences to the central unit, the received current / voltage characteristic curves being based on voltage and / or comparative data and / or differences evaluated by the central unit for multiple batteries with corresponding characteristic data.

[0042] For example, data from multiple batteries in a corresponding number of vehicles can be collected centrally and evaluated anonymously. The characteristic curve can then be adjusted based on the collected data and the corresponding battery conditions. Therefore, the characteristic curve received from the battery monitoring unit preferably corresponds to the empirical value of the battery with the corresponding battery state. Consequently, fault detection can be performed more accurately, and voltage changes can also be detected based on the (actual) characteristic curve, whereas situations where signals are output based on empirical values ​​would otherwise be ignored.

[0043] As described above, the corresponding current can be determined based on the current / voltage characteristic curve, which corresponds to a tap voltage or a comparison value, such as a determined difference in voltage variation characteristics. Based on the current and the difference, the total resistance of the corresponding battery pack can be calculated or determined, thereby leading to a more accurate conclusion about potential faults. To more accurately determine the potential increase in total resistance, the battery monitoring unit is preferably also configured to receive current from corresponding current sensors for at least two series-connected roof battery packs via an interface, and further output signals based on the corresponding currents.

[0044] This reduces the number of unknown variables and provides feedback on the expected current based on the characteristic curve, thereby further improving the reliability of the output signal.

[0045] The evaluation unit of the battery monitoring unit can also be configured to make comparisons in real time or at specified time intervals, for example, determining the comparison results and corresponding differences. In this way, the battery status can be continuously monitored so that a signal can be output immediately in the event of a serious fault. However, since the battery monitoring unit, in particular by determining the corresponding differences, improves battery safety and can even detect minor signs of faults, it is sufficient to determine the differences periodically or intermittently. For example, the difference can be measured only during normal or routine operation, preferably at time intervals of 1 minute to 1 hour, more preferably 5 minutes to 10 minutes.

[0046] Signals may include battery warnings, maintenance signals, and / or battery control signals.

[0047] For example, based on the determined difference, it can be assessed or determined that at least one battery cell in a particular battery pack has failed or appears likely to fail within a predetermined time. In this case, it might be sufficient to simply output a warning signal, such as via a communication module, to alert the user to the presence of the fault. Similarly, a maintenance signal could be output, for example, as part of a warning signal, to indicate that action is required, such as inspecting or maintaining the specific battery pack or module, or replacing the corresponding battery cell, battery pack, battery module, or the entire battery, to avoid any potential damage to the battery and the vehicle.

[0048] Furthermore, in the event of a serious malfunction, a control signal can be output to activate protective measures. This limits the battery's power, thereby limiting the maximum current load. Additionally, a contactor can isolate the battery from the electrical equipment to prevent current inflow. Through early fault detection and the output of corresponding signals, battery safety and the functionality of unaffected components are significantly improved. Even though early detection of potential faults can largely prevent the chain reactions that might occur with the aforementioned membrane-based current interruption devices due to aging or overload, this protective measure still provides sufficient safety for the battery in emergency situations.

[0049] The battery monitoring unit is applicable to a variety of applications and battery types. It is preferably used to monitor traction batteries. Therefore, this battery monitoring unit can be incorporated into modules such as those for electric vehicle traction batteries.

[0050] According to the present invention, the traction battery includes a battery monitoring unit, thereby further achieving the above-mentioned objectives.

[0051] For example, the traction battery may exhibit corresponding series battery packs with corresponding parallel battery cells, wherein each battery pack is provided with a voltage tap for communication and / or electrical coupling with the battery monitoring unit interface. Each battery pack preferably also includes multiple cylindrical battery cells. The interface may be a separate component of the battery monitoring unit or as part of the traction battery control unit, if the monitoring unit has been designed accordingly. The traction battery may also include contactors for isolation from the user and power terminals that may be configured or designed for the specific application of the battery. The traction battery is preferably configured for electric vehicles. Attached Figure Description

[0052] Other preferred embodiments of the present invention will be explained in more detail with reference to the following figures: Figure 1 This is a schematic diagram of the battery monitoring unit; Figure 2 A schematic diagram of a series battery pack arrangement is shown for providing voltage to adjacent battery packs; Figure 3 yes Figure 2 The schematic diagram shown illustrates an arrangement for supplying voltage to multiple battery packs; and Figure 4 yes Figure 2 The schematic diagram shown illustrates an arrangement used to provide voltage to non-adjacent battery packs. Detailed Implementation

[0053] Preferred embodiments will now be described with reference to the figures. In this regard, the same, similar, or analogous elements in the figures are given the same reference numerals, and to avoid redundancy, some repeated descriptions of these elements will be omitted.

[0054] Figure 1 The diagram schematically illustrates a battery monitoring unit 10, which may optionally be configured as a module capable of communicating with a battery control unit. The battery monitoring unit 10 includes an interface 12 configured to receive voltages 14A, 14B from a battery pack 22 of battery 1, the battery pack comprising at least two battery cells 24 connected in parallel, as indicated by arrows. The voltages 14A, 14B of the respective battery pack 22 are provided, for example, via voltage taps 28A, 28B..., 28E. Reference will be made below. Figures 2 to 4 Let me reiterate this point.

[0055] The first voltage 14A and the second voltage 14B are received via interface 12 as voltages of two battery packs connected in series. According to this embodiment, they are received by evaluation unit 16, which compares the received voltages 14A and 14B with each other, and in the specific embodiment described herein, determines the difference based on the received voltages 14A and 14B. Alternatively, a quotient can be derived from voltages 14A and 14B.

[0056] The voltages 14A and 14B that need to be compared can be measured through two conductors, where the battery packs can be either adjacent to each other or spaced apart.

[0057] In other words, there can be one or more battery packs between the battery packs used to measure voltages 14A and 14B. Similarly, voltages 14A and 14B can be measured sequentially across multiple battery packs via corresponding conductors.

[0058] Voltages 14A and 14B can be measured across a single battery pack or across multiple battery packs, so as shown in the diagram below, multiple battery packs can be compared with a corresponding number of different battery packs, rather than battery pack pairs.

[0059] The difference is then compared to a threshold, which can be an absolute value or a percentage. The absolute value can be either negative or positive, so that both overvoltage and undervoltage of the corresponding battery pack can be taken into account. Furthermore, the determined or identified difference can also be used as a percentage of the tap voltage of the battery pack constituting the difference, preferably a percentage of the corresponding lower voltage, which is compared to a predetermined percentage, thus the predetermined percentage can be considered as the threshold.

[0060] Based on the comparison between the difference and a threshold, if the difference exceeds the threshold, signal 18 can be output via interface 12. Alternatively, a specific size of difference or a difference greater than a predetermined minimum difference can be specified to automatically cause signal 18 to be output, for example, via appropriate circuitry.

[0061] In this example, signal 18 includes a warning signal and a potential control signal, specifically related to the magnitude of the determined difference. Thus, for example, a warning signal can be output if the determined difference indicates that one or more battery cells may fail in the foreseeable future, while a control signal can be output, particularly when the difference indicates that a serious failure may occur.

[0062] For example, signal 18 can limit the maximum current load by initiating safety measures that limit the battery's power. Similarly, a contactor can be used to isolate the battery from the electrical equipment to prevent current flow, such as triggering a cascading effect when a current interruption device is activated.

[0063] exist Figure 1 The diagram also shows an optional communication module 20, as indicated by the corresponding arrows, which is bidirectionally communicatively coupled to the evaluation unit 16. For example, communication module 20 can enable communication with the central unit 100 and / or the battery control unit. More application-specific signals or data can also be transmitted via communication module 20. For example, maintenance signals can also be transmitted to maintenance services in this way, where warning signals can be displayed on a screen. The central unit 100 may be a vehicle central control system, etc.

[0064] exist Figures 2 to 4 The diagram shows a schematic arrangement of a series-connected battery pack 22 for constructing battery 1, wherein a load is connected to a power supply terminal 26.

[0065] Among other things, battery pack 22 also provides voltages 14A and 14B for checking the corresponding operating status, wherein voltages 14A and 14B can be detected by battery monitoring unit 10 (e.g., Figure 1 (As shown) is received through interface 12.

[0066] In this example, the arrangement schematically illustrates the battery module, wherein the number of battery packs 22 connected in series should not be construed as limiting. Each battery pack 22 also includes a predetermined number (not limited in the figure) of battery cells 24, which are connected in parallel within the respective battery pack 22.

[0067] For example, the battery module schematically shown here can be used to construct the traction battery of an electric vehicle and can be electrically connected or coupled to a corresponding load via power terminal 26. To construct battery 1, multiple battery modules are typically required, which can be connected in series or in parallel to provide the required capacity and rated voltage.

[0068] according to Figure 2 The voltages 14A and 14B of adjacent battery packs 22 are tapped via corresponding voltage taps 28A, 28B, and 28C. Therefore, the voltage 14A of the upper battery pack 22 in the view is determined by voltage taps or conductors 28A and 28B, while the voltage 14B of the directly adjacent battery pack 22 (located directly below in the figure) is determined by voltage taps 22B and 22C. The difference between adjacent battery packs 22 determined by the battery monitoring unit 10 can output a signal 18 for a specific or particular individual battery pack 22, thus providing very precise monitoring of the battery status. In this example, potential faults within a specific battery pack 22 can be determined based on the difference and the determined values ​​of adjacent battery packs 22.

[0069] In this example, fault 30 is described by the symbol of battery cell 24 in the upper battery pack 22, which is arranged on the right side of the diagram. Therefore, exceeding the threshold may indicate an increase in voltage in that particular battery pack 22, so that, for example, the triggered membrane current interruption device of battery cell 24 can detect fault 30 early and avoid further damage due to potential chain reactions.

[0070] Figure 3 and Figure 4 This illustrates another method for determining the difference, in Figure 3 In the illustrated embodiment, the tap voltage 14A of one set of battery packs 22, namely the two upper battery packs 22, is compared with or provided to the tap voltage 14B of the two lower battery packs 22. Therefore, voltage taps 28A and 28C are used for voltage 14A, while voltage taps 28C and 28E are used for voltage 14B. Due to the multiplicity of the respective battery packs 22, monitoring can be simplified; for example, conclusions or assessments can be drawn regarding the presence of potential faults in specific areas of the battery packs. This method of indicating a region via signal 18 can be advantageous for battery packs with a large number of battery packs connected in series. Furthermore, this method typically reduces the required computational power or utilizes existing computational power to determine the difference and signal output at a higher time resolution.

[0071] Another method is as follows Figure 4 As shown, voltages 14A and 14B of non-adjacent battery packs 22 are received or supplied. This method of detecting voltages 14A and 14B via voltage taps 24A, 24B and 24C, 24D may have advantages, for example, that adjacent battery packs 22 may influence each other under specific operating conditions, thus negligible operational fluctuations. Thus, in some cases, the determined difference may be more representative, and the possible thresholds may include a smaller range of operational tolerances.

[0072] Furthermore, the difference can also be determined in this way, or for consecutive battery packs 22. According to this embodiment, the voltage 14A of the upper battery pack 22 is first compared with the voltage 14B of the adjacent battery pack 22, and then compared sequentially with the battery pack 22 arranged below it, and so on, thereby providing a certain safety redundancy. For example, Figure 2 and Figure 4 The combination of these parameters demonstrates the continuous (or parallel) determination of this difference. In an advantageous embodiment, voltage 14A is compared with the voltage of all individual battery packs 22. In this way, not only the voltages of adjacent battery packs 22 can be compared with each other, but the voltages of battery pack pairs (battery packs 22 that are not directly adjacent) can also be compared with each other to determine their respective differences.

[0073] Where applicable, all individual features described in the embodiments of the present invention may be combined and / or interchanged with each other without departing from the scope of the invention.

[0074] List of reference numerals 1 Battery 10 Battery Monitoring Unit 12 interfaces 14A First Voltage 14B Second Voltage 16 Evaluation Units 18 signals 20 Communication Module 22 battery packs 24 battery packs 26 Power terminals 28A-28E Voltage Tap Changer 30 Faults 100 Central Units

Claims

1. A battery monitoring unit (10) includes an interface (12) configured to receive voltages (14A, 14B) of each battery pack (22) of a battery (1), the battery pack including at least two battery cells (24) connected in parallel, the battery being coupled to the battery monitoring unit (10) and including at least two battery packs (22). in, An evaluation unit (16) is provided, which is configured to compare the voltages (14A, 14B) of at least two series-connected battery packs (22) received from the interface (12) and output a signal (18) based on the comparison result. The evaluation unit (16) is configured to determine the voltage difference and / or the voltage quotient for comparing the voltages (14A, 14B) received from the interface (12) and output a signal based on the difference and / or quotient. The evaluation unit (16) is also configured to determine the total resistance of the corresponding battery pack (22) based on the corresponding difference and / or quotient, the total resistance being a characteristic of the operating state of the battery pack (22).

2. The battery monitoring unit (10) according to claim 1, wherein, The evaluation unit (16) is configured to output a signal (18) when the corresponding difference exceeds a predetermined threshold or the corresponding quotient deviation reaches a predetermined level.

3. The battery monitoring unit (10) according to claim 1 or 2, wherein, The evaluation unit (16) is configured to output a signal (18) when the ratio of the difference to the voltage value of at least one of the battery packs (22) that form the difference reaches 0.01:1.0 to 0.25:1.

0.

4. The battery monitoring unit (10) according to claim 1 or 2, wherein, The evaluation unit (16) is configured to output a signal (18) when the ratio of the difference to the voltage value of at least one of the battery packs (22) that form the difference reaches 0.05:1.0 to 0.20:1.

0.

5. The battery monitoring unit (10) according to claim 1 or 2, wherein, The battery monitoring unit is configured to record the progress of the comparison results and to output a signal (18) when the progress deviates from the predetermined progress.

6. The battery monitoring unit (10) according to claim 1 or 2, wherein, The evaluation unit (16) includes a current / voltage characteristic curve and is configured to output a signal (18) based on the corresponding comparison results and the current / voltage characteristic curve.

7. The battery monitoring unit (10) according to claim 1 or 2, wherein, The battery monitoring unit is configured to receive characteristic data of the battery (1) through the interface (12), transmit the characteristic data to the central unit (100), and receive at least one current / voltage characteristic curve from the central unit (100) in response to the transmitted characteristic data, wherein the evaluation unit (16) is configured to output a signal (18) based on the corresponding comparison result and the current / voltage characteristic curve.

8. The battery monitoring unit (10) according to claim 7, wherein, The feature data includes battery type, number of parallel battery cells in each battery pack, battery cell type, number of series battery packs, application of battery (1) and / or operation data of battery (1).

9. The battery monitoring unit (10) according to claim 7, wherein, The battery monitoring unit is configured to transmit the received voltage (14A, 14B) and / or the corresponding comparison results to the central unit, and the received current / voltage characteristic curve is based on the voltage and / or comparison results evaluated by the central unit for multiple batteries (1) with corresponding characteristic data.

10. The battery monitoring unit (10) according to any one of claims 1, 2, 8, and 9, wherein, The evaluation unit (16) is also configured to receive current from the corresponding current sensors for the at least two series-connected battery packs (22) via the interface (12) and to continue to output signals (18) according to the corresponding current.

11. The battery monitoring unit (10) according to any one of claims 1, 2, 8, and 9, wherein, The evaluation unit (16) is configured to perform the corresponding comparisons in real time or at predetermined time intervals.

12. The battery monitoring unit (10) according to any one of claims 1, 2, 8, and 9, wherein, Signals (18) include warning, maintenance and / or control signals for the battery (1).

13. The battery monitoring unit (10) according to any one of claims 1, 2, 8, and 9, wherein, The comparison is performed accordingly for adjacent battery packs (22).

14. A traction battery comprising a battery monitoring unit (10) according to any one of claims 1-13, and comprising at least two battery packs (22), each battery pack (22) comprising a plurality of cylindrical battery cells (24) connected in parallel with each other.

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